xfs_dir2_block_compact() is passed a pointer to *blp, and
advances it locally - but nobody uses the pointer (locally)
This behavior came about as part of prior refactoring,
20f7e9f xfs: factor dir2 block read operations
and looking at the code as it was before, it seems quite clear
that this change introduced a bug; the pre-refactoring code
expects blp to be modified after compaction.
And indeed it did; see this commit which fixed it:
37f1356 xfs: recalculate leaf entry pointer after compacting a dir2 block
So the bug was introduced & resolved in the 3.8 cycle.
Whoops. Well, it's fixed now, and mystery solved; just remove
the now-pointless local increment of the blp pointer.
(I guess we should have run clang earlier!)
Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
diff --git a/fs/xfs/xfs_dir2_block.c b/fs/xfs/xfs_dir2_block.c
index 4f6a38c..5259939 100644
@@ -319,7 +319,6 @@ xfs_dir2_block_compact(
(xfs_dir2_data_aoff_t)((char *)blp - (char *)hdr),
(xfs_dir2_data_aoff_t)((be32_to_cpu(btp->stale) - 1) *
- blp += be32_to_cpu(btp->stale) - 1;
btp->stale = cpu_to_be32(1);
* If we now need to rebuild the bestfree map, do so.